Magnesium Protects Against Anaphylactic Shock and Cardiac Myolysis in Guinea-Pigs

The pathophysiological responses to immune stress (IS) include activation of several processes which are dependent on cytosolic Ca2+ elevation. Magnesium frequently acts as a natural Ca2+ antagonist. In this study we have observed that Mg2 + can protect guinea-pigs against IS. Antigen-sensitized guinea-pigs, which had been fed a magnesiumdeficient diet, were given a single dose (15 mg) of MgCl2 intraperitoneally 1 h before antigen challenge. The development of anaphylactic shock (AS) was observed during the next 2 h, and the hearts were subsequently examined histologically for signs of cardiac myolysis (CM). Magnesium (i) reduced the incidence of CM from 40% to 10% (p<0.05); (ii) reduced the incidence of AS from 61% to 35% (p<0.05); (iii) attenuated the severity of the AS; and (iv) lowered mortality from 39% in the control to 19% in the Mg2+-treated group (p=0.1). Serum and tissue total [Mg2+] were not affected by the administration of MgCl2. Also, the serum and heart Mg2+ levels were the same whether or not the guinea-pigs developed AS or CM. In cell culture we demonstrated that by elevating the [Mg2+] in the medium bathing sensitized rat basophilic leukemia (RBL) cells, the increase in cytosolic [Ca2+] subsequent to antigen challenge was reduced from 174 ± 23.28% (1 mM) to 82.74 ± 13.22 % (3 mM). We conclude that a single treatment with Mg2+ can considerably diminish damage induced by immune stress, probably by its altering the Ca2+: Mg2+ratio. Since the physiological reaction to different types of stress is similar, Mg2 + could prove beneficial in preventing stress-induced shock in general. Studies examining the mechanisms by which Mg2 + exerts its effects thus provide a scientific basis for the current clinical use of Mg2 + in acute myocardial infarction (AMI) and asthma.